In failure analysis, demounting and mounting is one of the steps in preparation for the electrical verification of the device. Performing decapsulation while the unit is mounted on the printed circuit board (PCB) is one of the solutions to limit the repeated demounting, mounting, and re-balling processes. However, it can cause inadvertent damage to the device and the PCB when the acids overflow, which could hinder further electrical verification of the unit. In this study, a new method of decapsulation using aluminum tape is used to protect the device and PCB during the decapsulation process. Results show that the use of aluminum tape is an effective method for decapsulating packaged units on PCB. It can prevent damages such as external lead detachment after demounting, ball pad oxidation, and recovery of device failure due to heat application.

MEMS samples, with their relatively large size and weight, present a unique challenge to the failure analyst as they also included thin films and microstructures used in conventional integrated circuits. This paper describes how to accommodate the large MEMS structures without skimping on the microanalyses needed to get to the root cause. Investigations of tuning folk gyroscopes were used to demonstrate these new techniques.